ptx

GNU `ptx' is the GNU version of the traditional permuted index
generator. It can handle multiple input files at once, produce TeX
compatible output, and produce readable "KWIC" (KeyWords In Context)
indexes without needing to use `nroff'. This version does not handle
input files that do not fit in memory all at once.

ptx is no longer a separate distribution; it is now released as
part of textutils, which can be found on in the subdirectory
/gnu/textutils/ on your favorite GNU mirror. For other ways to obtain
textutils, please read How to get GNU
Software .